Today's 3 Worst Stocks in the S&P 500

Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Well, it took a number of weeks, a government shutdown, and a last-minute deal to do it, but it looks like the debt ceiling debacle and government shutdown are finally behind us -- for now. The Senate deal, widely expected to be approved by the House of Representatives later this evening, would fund the government until Jan. 15, while pushing the next debt ceiling crisis forward through Feb. 7. The S&P 500 Index rewarded Washington's decision by adding 23 points, or 1.4%, to end at 1,721.

But rising tides rarely lift all boats in the stock market. Teradata again ended as one of the S&P's more extreme decliners, slumping 3.2% today as fallout over its anemic earnings outlook continued to hit shares. Today's 3% decline is small potatoes compared to yesterday's precipitous 18.4% meltdown, but it's clear that the data storage company shocked investors with its spooky earnings warning a few days ago.

Exelon , a $24 billion diversified utility company, shed 2.6% Wednesday, though there was little negative news with the company. Last week Exelon was dealt a blow in the court system, however, when a federal judge ruled the company couldn't use about $1.7 billion worth of charges related to decommissioning nuclear power plants to avoid taxes. With Wall Street in a "risk-on" mood today, it's no surprise that some defensive utilities stocks like Exelon underperformed.

Lastly, specialty metals producer Allegheny Technologies lost 1.9% Wednesday. The pullback comes after a rally Tuesday on the heels of Allegheny's newly outlined plans to restructure its business. The Engineered Products business segment will see the biggest changes, as the company divests from its iron casting business. While this is aimed at improving long-term results, short-term results aren't looking so rosy: Allegheny also forecast losses in its third quarter. Long-term sustainability at the expense of short-term profits is generally a sound trade-off for investors, as long as that long-term benefit eventually materializes. {%sfr%